Description: Cover of the October 1920 issue of Popular Science magazine, painted by American illustrator Norman Rockwell. It depicts an inventor working on a perpetual motion machine. The device shown is a "mass leverage" device, where the spherical weights on the right have more leverage than those on the left, supposedly creating a perpetual rotation, but there are a greater number of weights to the left, balancing the device.Title: Perpetual Motion by Norman RockwellCredit: Downloaded 2009-06-29 from Popular Science magazine, Vol.97, No.4 (October 1920), Bonnier Corp. New York, ISSN 0161-7370, front cover on Google BooksAuthor: Norman RockwellPermission: Public Domain in USA - published before 1923 in USAUsage Terms: Public domainLicense: Public domainAttribution Required?: No